Motor vehicle safety device for protecting pedestrians and cyclists

ABSTRACT

A motor vehicle safety device for protecting pedestrians and cyclists includes at least one airbag that is connected to a gas generator arranged under the engine hood. The airbag is deployable to protect a pedestrian or a cyclist who strikes the vehicle. To prevent the lateral displacement of the segments of the deployed airbag in front of the A-pillars of the vehicle, the airbag, which is deployed from below the engine hood, includes a section or a chamber near the hood&#39;s hinges. As a result, the airbag is deployable above the hood along the entire width of the vehicle in front of the lower area of the windshield and the A-pillars. The airbag lateral ends of the airbag extend over the A-pillars in such a way that they are upwardly oriented and additionally fixed after deployment.

The invention relates to a motor vehicle safety device for protectingpedestrians and cyclists, in accordance with the precharacterizingclause of claim 1.

In addition to other safety devices for protecting pedestrians andcyclists (EP 0967 128 A2, DE 101 02 597 A1, DE 100 14 832 A1), a motorvehicle airbag system is known (EP 1 176 062 A2) having airbags whichcover the region of the A pillars of the motor vehicle in the case of anaccident with a pedestrian or cyclist. Said airbags are intended, inparticular, to lessen the impact of the head onto the A pillar. Saidairbags cover only a small part of the windshield, in order not toimpede the vision of the driver, and are therefore narrow and unstableon account of the small volume. This results in the disadvantage that,in the event of an oblique impact of a person, said airbags can bepushed to the side by said person, with the result that the personcollides with motor vehicle parts, in particular with the A pillar, andthe intended protection cannot occur.

The invention is therefore based on the object of preventing thecollision of a pedestrian or cyclist with the A pillar and adjoiningparts of the motor vehicle, even in the event of an oblique collision,in the case of a safety device which also ensures good vision for thedriver after the collision.

According to the invention, this is achieved in accordance with thefeatures of claim 1.

In a motor vehicle safety device for protecting pedestrians andcyclists, having at least one airbag which is arranged under the enginehood, is connected to at least one gas generator, unfolds to protect apedestrian or cyclist who strikes the vehicle and, in the process,initially lifts up the engine hood from the motor vehicle, at least atthe location of the unfolding of the airbag, to such an extent that theairbag can unfold outwardly in a second phase, according to theinvention, in the unfolded state, the airbag has two chambers under theengine hood in the region of the hinges of the engine hood. The airbagextends above the engine hood over the entire width of the motor vehiclein front of the lower region of the windshield and the A pillars of themotor vehicle, and the lateral ends of the airbag which, in particular,cover the A pillars point upward after the unfolding of said airbag andare additionally fixed. The unfolded airbag thus has a U shape.

The result of minimizing the displacement of the upwardly pointing endswhich cover the rigid regions of the vehicle adjoining the engine hoodis a high and reliable potential for protection. Additional fixing ofthe upwardly pointing ends ensures the protection against collision, inparticular, with the A pillars, even in the event of an obliquecollision, for example from the center of the windshield. The forces areintroduced favorably by raising the engine hood over a wide area in thehinge region, which leads to relatively small deformations of the enginehood and thus to a reduction in oscillations.

The lateral ends can be fixed in different ways.

At least one intercepting strap or one tube-shaped airbag can thus beprovided as a means for fixing the lateral ends of the airbag. Here,there is provision in one embodiment for the lateral ends of the airbagto be connected to one another by an intercepting strap or a tube-likeairbag. There is provision in a further embodiment for the lateral endsof the airbag to be connected to the lower region of the airbag sectionwhich lies on the opposite vehicle side via intercepting straps whichextend crosswise or via tube-like airbags.

There is provision in a third embodiment for the lateral ends of theairbag to be fixed by intercepting straps or tube-like airbags, theother ends of which are fastened to the motor vehicle, for example areconnected to the central section of a module housing which is arrangedbelow the engine hood.

There is provision in a further embodiment for each lateral end of theairbag to be fixed by two intercepting straps or two tube-like airbagswhich emerge from the outer side and the inner side of the respectivelateral end.

The lateral ends can also be stabilized by providing reinforcements ofthe airbag in this region. At least one seam can be provided asreinforcement. However, at least one transparent airbag can also beprovided as reinforcement. In one embodiment, at least one transparentreinforcement airbag is arranged between the lateral ends. In a furtherembodiment, at least one transparent woven fabric insert extends fromeach lateral end into the central region of the airbag.

A further possibility for supporting the lateral ends of the airbagconsists in that a guide system which is connected to the airbag isprovided in the region of the A pillars, with the aid of which guidesystem the lateral ends of the airbag are guided during its unfolding.The guide system preferably has a guide rail on each A pillar, on whichguide rail a guide part which is connected to the airbag can bedisplaced during the unfolding of the airbag.

The at least one gas generator is connected to those sections orchambers of the airbag which lie below the engine hood in the unfoldedstate directly or indirectly via feed lines. This achieves the situationin which first the region of the airbag below the engine hood is filledand subsequently the airbag volume for the adjoining regions.

The airbag has at least one outflow opening for energy absorption bymeans of said airbag. In an airbag without an outflow opening, saidairbag is subdivided into chambers by tucks or dividing walls for energyabsorption by means of said airbag. The chambers are connected to oneanother in such a way that a volume can be displaced between themcounter to a defined amount of resistance, that is to say the energy isabsorbed by the work carried out to displace the volume between thechambers.

The invention is to be explained in exemplary embodiments using thedrawings, in which:

FIG. 1A shows a detail of the front view of a motor vehicle with anunfolded airbag and a first embodiment of the additional fixing meansfor the lateral ends of the unfolded airbag;

FIGS. 1B, 2A and 2B show the detail according to FIG. 1A with threefurther embodiments of the fixing means for the lateral ends of theunfolded airbag;

FIG. 3 shows an embodiment having stabilizing tucks in the woven fabricof the airbag;

FIG. 4 shows an embodiment of the airbag having transparent woven fabricinserts;

FIG. 5 shows an embodiment having a guide system for the lateral ends ofthe airbag; and

FIG. 6 shows an airbag in the unfolded state, said airbag havingseparate chambers below the engine hood.

The arrangement of the airbag 1 in the front region of a motor vehiclecan be seen from FIGS. 1A, 1B, 2A, 2B, 4 and 5. The figures show the Apillars 17, 18 and the engine hood 19. An airbag is shown in anembodiment having chambers 15, 16 which lie below the engine hood 19 inthe region of hinges 19 a, 19 b in the unfolded position shown. Theairbag is assigned a module housing 20 which is arranged below theengine hood 19 and has at least one gas generator (not shown). Thelateral ends 2, 3 of the airbag are additionally fixed in the embodimentof FIG. 1A by an intercepting strap 21 which extends between the ends 2,3. As a result, the lateral yielding of the ends is prevented to a verylarge extent, even in the event of a lateral impact of a person. As theintercepting strap is narrow, the vision of the driver is barelyimpeded.

The same effect is achieved if, instead of the intercepting strap, atube-shaped airbag 21 a is provided, the diameter of which correspondsat least approximately to the width of the intercepting strap 21.

In the embodiment of FIG. 1B, two intercepting straps 22, 23 orcorresponding tube-shaped airbags 22 a, 23 a which extend crosswise areprovided. Here, one end of the intercepting strap 22 is connected to thelateral end 2, while the other end is connected in the region of thechamber 16 to the airbag section lying opposite. One end of theintercepting strap 23 is connected at the lateral end 3 of the airbagand the other end is connected in the region of the chamber 15 to theairbag section lying opposite.

In both embodiments, transparent airbags 24 for stabilizing the lateralends 2, 3 could be provided instead of the intercepting straps ortube-shaped airbags of small diameter, the upper edge of which isindicated in each case by a dashed line in FIGS. 1A and 1B. Saidtransparent airbags impede the vision of the driver only to a minimumextent.

In the embodiment of FIG. 2A, intercepting straps 25, 26 or tube-shapedairbags 25 a, 26 a extend from the inner sides 27, 28 of the lateralends 2, 3 of the airbag 1 to the central region of the module housing 20and are connected to the latter there. In a further embodiment, as shownin FIG. 2B, intercepting straps 31, 32 or tube-shaped airbags 31 a, 32 aadditionally also extend from the outer sides 29, 30 of the lateral ends2, 3 to the edge regions of the module housing 20 and are connected tothe latter there.

In the embodiment of FIG. 3, tucks 33 are provided for stabilizing thelateral ends 2, 3.

In the embodiment of FIG. 4, the lateral ends 2, 3 are provided by meansof transparent woven fabric layers 34, 35 which extend obliquelydownward from the inner sides 27, 28 of the lateral ends 2, 3 of theairbag and are connected to the airbag there in the central section ofsaid airbag.

FIG. 5 shows an embodiment in which the lateral ends 2, 3 are connectedto a guide system. In the region of the A pillars, said guide system hasguide rails 36, 37 which extend as far as under the engine hood 19. Saidguide rails are assigned guide parts 38, 39 which are connected to thelateral ends 2, 3 on the rear side of the latter. Said guide partsenclose the guide rails, so that they are not released from them and canmove only in their longitudinal direction. During the unfolding of theairbag, the guide parts 38, 39 slide on the guide rails 36, 37 from thebottom to the top, until they have reached the end position which isshown in FIG. 5.

In all the embodiments shown, only the lower region of the windshield iscovered by the airbag 1 as a consequence of the U shape of the unfoldedairbag. Secondly, however, the region of the A pillars is covered stablyby the airbag, with the result that, even in the event of an obliqueimpact of a person, displacement of the related airbag sections isprevented to a very large extent.

In the embodiment of FIG. 6, there are two chambers 15, 16 which arearranged in the region of the hinges 19 a, 19 b of the engine hood 19.

Two possibilities are shown in this figure for improving the dissipationof energy during the impact of a pedestrian or cyclist. The lateral end2 is thus separated from the remaining region by tucks 4 a, b, whichleaves only a small opening 5 for the entry of gases into the lateralend, with the result that a separate chamber is formed. Although thisopening allows rapid unfolding of the airbag on account of the highpressure of the gases, volume equalization to the remaining airbagregion is delayed in the event of a collision of a person, that is tosay resistance is generated to the displacement of the gas volume fromthe impact region as a result of the subdivision of the gas sack intochambers and appropriately dimensioned overflow regions. In thisembodiment, the upper part 1 b has a further chamber 1 c which likewiseserves to improve the dissipation of energy in the impact region.

The dissipation of energy is improved at the lateral end 3 by a tuck 6which extends in the center thereof.

Tucks 9, 10 which leave only small openings 11 to 14 between the parts 1a and 1 b are provided between those chambers 15, 16 of the airbag whichremain below the engine hood after the unfolding of the airbag and thepart 1 b of the airbag. This achieves the situation in which thechambers 15, 16 which lift up the rear region of the engine hood (notshown here) unfold first of all, with the result that the part 1 b cansubsequently unfold above the engine hood in front of the lower regionof the windshield and the A pillars.

1-19. (canceled)
 20. A motor vehicle safety device for protecting pedestrians and cyclists comprising: an airbag that is configured to be arranged under a hingedly connected hood of the vehicle; and a gas generator connected to the airbag, wherein, during inflation, the airbag is configured to lift at least a portion of the hood such that a section of the airbag can thereafter unfold onto an A-pillar and a lower portion of a windshield of the vehicle, wherein, when unfolded, the airbag is configured to include a chamber located below the hood in the vicinity of one of the hinges of the hood, and a lateral end of the airbag, which is configured to cover the A-pillar, points upward, and wherein the airbag section, which is configured to unfold onto the A-pillar, is fixed by a restraining member to prevent lateral displacement.
 21. The safety device of claim 20, wherein the airbag is configured so that, when inflated, the airbag extends over the entire width of the vehicle into a position in front of both A-pillars.
 22. The safety device of claim 20, wherein the restraining member is an intercepting strap.
 23. The safety device of claim 20, wherein the restraining member is a tube-shaped airbag.
 24. The safety device of claim 20, wherein the restraining member is an intercepting strap or a tube-like airbag that connects the lateral ends of the airbag together.
 25. The safety device of claim 20, wherein the restraining member includes a pair of intercepting straps or tube-like airbags, wherein a first of the pair of intercepting straps or tube-like airbags connects a first lateral end of the airbag to a portion of the airbag that is located below the hood and on an opposite, second side of the vehicle, and wherein a second of the pair of intercepting straps or tube-like airbags connects a second lateral end of the airbag to a portion of the airbag that is located below the hood and on an opposite, first side of the vehicle.
 26. The safety device of claim 25, wherein the straps or tube-like airbags cross in a central portion of the vehicle.
 27. The safety device of claim 20, wherein the restraining member includes a pair of intercepting straps or tube-like airbags, wherein a first end of a first of the pair of intercepting straps or tube-like airbags is connected to a first lateral end of the airbag and a second end of the first of the pair of intercepting straps or tube-like airbags is connected to the vehicle, and wherein a first end of a second of the pair of intercepting straps or tube-like airbags is connected to a second lateral end of the airbag and a second end of the second of the pair of intercepting straps or tube-like airbags is connected to the vehicle.
 28. The safety device of claim 27, wherein the second ends of the intercepting straps or tube-like airbags are connected to a central section of a module housing that is part of the vehicle and is located below the hood.
 29. The safety device of claim 20, wherein the restraining member includes two pairs of intercepting straps or tube-like airbags, wherein a first of the two pairs of intercepting straps or tube-like airbags restrains inner and outer sides of a first lateral end of the airbag, and wherein a second of the two pairs of intercepting straps or tube-like airbags restrains inner and outer sides of a second lateral end of the airbag.
 30. The safety device of claim 20, further comprising a reinforcement mechanism provided in the vicinity of each of the lateral ends of the airbag.
 31. The safety device of claim 30, wherein the reinforcement mechanism is a seam.
 32. The safety device of claim 30, wherein the reinforcement mechanism is a transparent airbag provided between the lateral ends.
 33. The safety device of claim 30, wherein the reinforcement mechanism is a transparent woven fabric insert extending from each lateral end into a central region of the airbag.
 34. The safety device of claim 20, further comprising: a guide system for guiding the lateral ends of the airbag during inflation, wherein the guide system is connected to the airbag and is provided in the vicinity of the A-pillar.
 35. The safety device of claim 34, wherein the guide system has a guide rail on the A-pillar, wherein a guide part is provided on the guide rail, and wherein the guide part is connected to the airbag and is configured to be displaced during inflation of the airbag.
 36. The safety device of claim 20, wherein the chamber is fluidly connected to a gas generator via feed lines.
 37. The safety device of claim 20, wherein the airbag includes at least one outflow opening for energy absorption.
 38. The safety device of claim 20, wherein the airbag is subdivided into at least four chambers by tucks and/or dividing walls.
 39. The safety device of claim 38, wherein the airbag comprises an additional chamber connected to the first mentioned chamber and is configured so that a volume can be displaced between the two chambers for energy absorption. 